1. Field of the Invention
The current invention relates to electronic component packages and to electromagnetic interference (EMI) shielding. More particularly, the invention relates to electronic component packages, such as system-in-package modules, with EMI shielding to isolate a component in the package from electromagnetic interference, or from causing electromagnetic interference, in other parts of the package.
2. Background Information
System-in-package (SiP) technology is an integrated module design that contains one or more IC chips and associated discrete components for performing an entire electronic circuit function incorporated into a single encapsulated package. Electromagnetic interference (EMI), also known as radio frequency interference (RFI), is caused by electromagnetic radiation emitted by electronic circuits and components carrying changing electrical signals. EMI is a major consideration in single package design especially where EMI sensitive and/or RF components are tightly packed together, which is becoming increasingly common place with the proliferation of wireless technologies into a range of small scale electronic devices.
The most popular form of shielding within SiP modules is through use of a shielding lid to enclose the sensitive or EMI generating component. The component is mounted on an area of a supporting substrate with a ground trace plane beneath it and a metal box, or other shaped, lid is mounted over the component to enclose the component in a conductive enclosure. Metal lids of this type take up considerable space on the substrate surface and tended to be not very robust often dislodging from the substrate surface due to cyclic stress loading on the solder joints holding the lid to the substrate. This problem is ameliorated to some extent by overmolding or encapsulation of the package, including the lid, in resin to protect the package and components from mechanical damage, shock and moisture. However, the lid must have openings in its top and sides to facilitate the flow of the encapsulating resin. The amount and size of these openings is restricted to avoid EMI leakage, particularly for high frequency operations. The flow of encapsulating resin is therefore restricted often resulting in air spaces within the shielding lid. The openings are subsequently blocked by the resin trapping this air within the lid, which is hazardous to package reliability during subsequent thermal excursions and can result in cracking and dislodging of the shielding lid.
Accordingly, is an object of the present invention to provide an electronic component package having EMI shielding for sensitive electronic or EMI generating components that overcomes or at least ameliorates the above problems.